Analysis of Myopodin in Hela Cervical Carcinoma Cells

Abstract

Synaptopodin-2 is a proline-rich, actin-binding protein that exists in many isoforms. Due to its large proline content, synaptopodin-2 exists in a naturally unfolded state and possesses the characteristics of a hub protein. Members of the synaptopodin-2 family have been shown to bind with actin and induce actin polymerization (Chalovich and Shroeter, 2010). It has been found that synaptopodin can regulate [alpha]-actinin, which has actin-bundling activity (Asunama 2005). This interaction is isoform specific and causes bundling and elongation of [alpha]-actinin-induced actin filaments. The significance of possessing the ability to stimulate actin and induce actin bundling lies in the fact that the remodeling of the actin polymers is important for cell migration, adhesion, division and development. Cancer cell metastasis is a multi-stage process involving invasion into surrounding tissue (intravasation) transit in the blood or lymph (extravasation) and growth at a new site. Many of these steps require cell motility, which is driven by cycles of actin polymerization, cell adhesion and acto-myosin contraction (Olsen 2008). Therefore studies have been completed to answer the role of synaptopodin-2 in cancer and contradicting results have been obtained. Interestingly, contradicting results have also been observed for other actin binding proteins: gelsolin, CapG, and [alpha] actinin (De Ganck 2009); therefore not allowing actin-binding proteins to be classified as tumor activators or suppressors. This work provides evidence of syanptopodin-2, isoform myopodin, functions as a tumor suppressor and also suggests the existence of another isoform of synaptopodin-2 in Hela cells.